Patchy particles are a class of anisotropic particles that are characterized by having one or more surface-exposed domains with different surface chemistry relative to the rest of the particle. The anisotropic feature of nano- and micron-size patchy particles can be created using several techniques including template-assisted fabrication, electrified jetting, glancing angle deposition, lithography, and phase segregation. The anisotropic feature is advantageous because it allows fabrication of systems at nano- and micron-scale sizes that can perform multiple functions. The patchy polymeric particles provide the ability to simultaneously present two different surface chemistries on the same particle. There are diverse medical and industrial applications that may benefit from the use of patchy-lipid polymer particles including vaccines, drug delivery, sensors, photonics, imaging, tissue engineering and environment chemistry.
There is a need in medicine for the development of theranostic devices, which are systems that perform at the same time therapeutic and imaging functions. In cancer, theranostic devices are needed because they can be used to distribute a drug homogenously in the tumor vasculature by assistance of an imaging function. In this way, the multi-drug resistance phenomenon, which is often observed in cancer, may be significantly diminished. In tissue engineering, a patchy surface can uniquely advance medicine as it allows functionalizing the patches with multiple ligands to target different types of cells. In biomedical imaging, the patch cluster effect can significantly enhance the imaging signal due to the high density of imaging molecules in a well-defined region of the carrier.
Methods are known in the art for synthesizing patchy particles. For example, the synthesis of lipid polymeric patchy particles is described in “Spontaneous Formation of Heterogeneous Patches on Polymer-Lipid Core-shell Particle Surfaces during Self-Assembly”, Small, 2012. The particles can be synthesized using nanoprecipitation and emulsion methods.
Particle formation depends on physical and mechanical parameters. The shear stress that a polymer blend undergoes during the emulsification step in the particle's synthesis has been found to be an important parameter for the formation of particles with patches. Thus, it is desirable to evaluate the role of the shear stress in the formation of the internal and external morphology of lipid polymeric patchy particles with single and multiple patches.